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Updated: Jul 6, 2026
08:55
High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy
Published on: October 9, 2020
Spin dynamics in the modulation frame: application to homonuclear recoupling in magic angle spinning solid-state NMR.
Gaël De Paëpe1, Józef R Lewandowski, Robert G Griffin
1Francis Bitter Magnet Laboratory and Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
The Journal of Chemical Physics
|April 2, 2008
Summary
We developed new solid-state NMR pulse sequences for magic angle spinning dipolar recoupling. These methods, CMpRR and COMICS, enable efficient recoupling at high frequencies, advancing biomolecular studies.
Area of Science:
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy
- Advanced pulse sequence development
- Biomolecular structure and dynamics
Background:
- Magic angle spinning (MAS) is crucial for high-resolution solid-state NMR.
- Dipolar recoupling experiments are essential for structural information but face limitations.
- Existing methods struggle with high spinning frequencies and strong interactions.
Purpose of the Study:
- Introduce a generalized family of solid-state NMR pulse sequences.
- Develop novel approaches for magic angle spinning dipolar recoupling.
- Focus on two specific mechanisms: CMpRR and COMICS.
Main Methods:
- Developed cosine modulated rotary resonance (CMpRR) for broadband double-quantum (DQ) carbon-13 (¹³C) recoupling.
- Implemented cosine modulated recoupling with isotropic chemical shift reintroduction (COMICS) for selective recoupling.
- Utilized gamma-encoded sequences with modulated radiofrequency (rf) phases.
Main Results:
- CMpRR achieves >70 kHz ¹³C DQ recoupling at spinning frequencies of 10-30 kHz and high proton (¹H) Larmor frequencies (up to 900 MHz).
- CMpRR efficiently recouples without ¹H decoupling for p≥5, and with low-power ¹H irradiation for lower p values.
- COMICS provides selective ¹³C DQ recoupling (approx. 100 Hz bandwidth) by reintroducing isotropic chemical shift information, circumventing dipolar truncation.
Conclusions:
- The new pulse sequences generalize second averaging in the modulation frame.
- These techniques mitigate heating effects and extend homonuclear recoupling to new regimes (high spinning and Larmor frequencies).
- The developed methods are highly relevant for high-resolution biomolecular NMR studies.
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